1. Field of the Invention
The present invention relates to an image recording apparatus and an image recording method and, more particularly, to an image recording apparatus and an image recording method for fixing an image on a recording medium by radiating an ultraviolet-ray.
2. Description of the Related Art
As a system for recording an image to an recording medium having no particular image reception layer, UV (ultraviolet) ink jet recording system which uses UV curable ink has been known, in which a recording medium is irradiated with UV-rays after the UV curable ink was jetted thereon to cure and fix the UV curable ink, thereby recording an image on the recording medium (see, for example, JP-Tokukaihei-6-200204A and JP-Tokukai-2000-504778A). Since the UV curable ink is fixed on a recording medium which is not specially treated, an image can be recorded on various types of recording medium. A recording medium containing no chemical compound inhibiting ink curing with-UV-rays, such as a printing paper, copy paper, synthetic paper, various types of plastic films, various metals, wood, glass, various cloths or the like, can be employed in the UV ink jet recording system.
In the ink jet recording system, a plurality of recording modes each having an image recording speed which is different from others are provided to be able to select a recording mode according to a type of recording medium or a demanding image quality. For example, in the case that a positional relationship between a recording head and a UV irradiation device is fixed such as an image recording apparatus of serial print type in which the recording head of the ink jet system and the UV irradiation device are mounted on a same carriage, the exposure condition is changed by changing a recording mode. To put it concretely, when a recording mode is changed to increase an image recording speed, factors such as timing from jetting ink to exposure, exposure time, exposure record of base ink at a portion on which ink is reprinted is changed, causing irregularity of an image quality and ink curing property.
It is effective to appropriately change the arrangement of the irradiation device and the recording head, illuminance of a light source, a light emitting area of a light source and irradiation time to stabilize these properties corresponding to a recording mode, however, a specific contrivance is required for the apparatus.
In the serial print type in which the recording head of ink jet system and the light source are mounted on the same carriage, it is preferable to use a small and lightweight light source as far as possible for minimizing the size of the carriage. Since the output of a small light source has a limit, the ink may not be cured enough, particularly, in the case of using an apparatus in which an amount of ink jetted per unit of time is large.
Moreover, in a process color printing of yellow (Y), magenta (M), cyan (C), and black (Bk), since the surface of ink is not cured enough at a portion where the amount of ink is large, an image blurs. Even when the surface of the ink can be cured enough, a problem occurs that the ink is not cured enough inside thereof, causing a deterioration of adhesiveness to a substrate and wrinkles by ink shrinkage on the surface.